Kitchen gardens, in which flowers and vegetables are grown, are becoming more and more popular in Japanese homes and apartments these days. The beneficial effects of fragrance and of pets, respectively called aromatherapy and animal therapy, have been confirmed and are conventionally used in medical institutions and similar therapeutic settings. In recent years, the healing effects of growing and viewing plants, “green therapy,” has also been studied and is also attracting increasing attention.
There are two ways to obtain a plant for the kitchen garden or for other use: buying a seedling; and buying a seed, germinating it, and raising the seedling oneself. Since buying a seed to germinate is troublesome and requires some skills compared to buying a seedling, beginners in particular usually buy a seedling.
Since most of the commercially available seedlings are, generally speaking, of standard breeds, seedlings of new breeds and special plants are difficult to obtain, and seedlings are more expensive than seeds, the more advanced gardeners tend to buy seeds to germinate and to raise them to full growth themselves. The problem here, however, is that seeds of plants have different optimum temperatures for germination in accordance with their kind. Pansies, for example, can bloom as early as December in eastern Japan, for which the seeds must be sown from late September to early October in order for the seeds to germinate and seedlings to grow. However, the optimum temperature for the germination of pansy seeds is between 15° C. and 20° C.: hence this period is too hot for the seeds that they are prone to perish, thus reducing their germination rate in a general environment. If the seeds are sown after November, in which the temperature reaches the optimum temperature for germination, their germination rate rises. Nevertheless, the seedlings grow slowly because of the low temperature in raising them, and it is difficult for them to bloom before the end of the year.
In the case of tropical plants, the optimum germination temperature for the bitter melon, for example, is between 25 and 35° C., and the soil temperature reaches this optimum temperature for germination after the middle of June in the east area of Japan. Since it takes approximately 60 days to raise a seedling after germination until the harvest, the harvest is started after August. In addition, since the growth rate of bitter melon quickly decreases when the temperature is under 20° C., the harvest period is limited to approximately 2.5 months, from August to the middle of October.
Nevertheless, if a plant is taken care of at an appropriate temperature during the period of the germination and of the emergence of the young seedling, it can grow after that even if the temperature is a little higher or lower than the optimum temperature. Hence, if an appropriate temperature control is performed during this period, for example, the seeds of pansy, which is suitable for low temperatures, can be sown in September to raise the seedlings so that it blooms in December. If bitter melon or other tropical plants are germinated in March through April and the seedlings are raised and settled in April through May, it is possible to start the harvest from July, which extends the harvest period by more than one month.
Given these factors, with the aim of germinating seeds and growing young seedlings at an appropriate temperature, a plurality of germination/growing apparatuses have been conventionally available in the market. These apparatuses usually comprise: a heat shield chamber capable of containing a seed or plant; means for controlling the temperature of the inside of the heat shield chamber; means for illuminating the inside of the heat shield chamber; and other portions, where seeds or plants with different optimum temperatures for germination and for raising the seedling can be germinated or grown without the influence of season and weather (for example, refer to Patent Document 1).    [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2006-61126